Grinding and sieving caustic alkali



W. J. MBNZIES. `GRINDING AND SIEVING GAUs-TIG ALKALI.

(No Model.)

Patented July 15, 1881.

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No. 243,9329-.f

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UNITED STATES PATEXNT OFErcE.

WILLIAM J. MENZIES, OF ST. HELENS, COUNTY OF LANCASTER, ENGLAND,ASSIGNOR OF ONEHALF TO GEORGE T. LEWIS, OF PHILADELPHIA,

PENNSYLVANIA.

GRINDING AND SIEVING CAUSTIC ALKAL SPECIFICATION forming part of LettersPatent No. 243,939, dated July 5, 1881.

` Application led December 1, 1880. (No model.) Patented in EnglandOctober 21; 1879.

To all 'whom it may concern:

Beit known that I, WILLIAM J oNEs MEN- ZIEs, a British subject, residingin St. Helens, in the county of Lancaster, England, have inventedcertain new and useful Improvements in Grinding` and Sieving CausticAlkalies, and in apparatus therefor, (for which I have received LettersPatent in England, No. 4,274, dated October 21, 1879,) and I do herebydeclare that the following is a full, clear, and exact description ofthe invention, which will enable others skilled in the art to which itaptertains to make and use the same.

I find, however, that by grinding or crushing caustic alkalies while hotthe deliquescence is not perceptible, and by grinding or crushing andimmediately sieving in a close mill the dust-nuisance is minimized. Imelt the caustic alkalies and pour them onto suitable plates, and whenconsolidated, but still ata high temperature-sufficiently high toprevent any perceptible deliquescence--grind and sieve the same bypassing them through a suitable mill; or, if the caustic alkalies havebeen allowed to cool, they may be ground and sieved by heating the mill,or the atmosphere through which they pass, to a temperature sufficientlyhigh to prevent any perceptible deliquescence, as if the causticalkalies were hot, by steam-pipes or other well-known mechanical meansfor applying heat. In grinding and sieving the caustic alkalies I usepreferably an ordinary grinding and sieving clay-mill, but covered inbelow with a stationary bottom underneath, and scraper moving aroundupon it and scraping the sieved and powdered alkali (which has fallenthrough the sieveplates above onto thebottom ofthe closed chamber below)out through apertures at the bottom into the barrel placed underneath,as shown in the annexed drawings, in which- Figure lis an elevation,Fig. 2 section, of my improved apparatus.

A A arek the grinding-rollers, as in an ordinary mortar or clay mill; B,shaft carrying same a a, scrapers bearing against periphery of rollers AA; C, steel or other hard plate carried by cast-iron-pan D, which latteris keyed to shaft E and rotated by bevelgearing I G,

ily-wheel H, crank I, and engine J; K, walls 5o of pan; L, grating; M,stationary bottom; N, scrapers, scraping the finelypowdered and sievedcaustic that falls on the sheet in bottom M into spout P in said bottom,through which the powder falls into a barrel, Q, preferably placed on atrolley, as shown.

Many other forms of combined sieve and grinder will do, so long as thesieving immediately follows the grinding, and the caustic alkalies areground hot, or the mill and appa- 6o ratus or atmosphere in connectionwith or surrounding the same is sufficiently heated by steam-pipes orother suitable means for applying the heat.

In actual practice I use caustic sufficiently hot, and guard it fromcurrents of air, and pass through such a quantity in such a manner as toavoid having'to heat the mill with steampipes, 85e. but, if desirable,the pan could be made hollow, and steam be made to circulate 7o betweenthe plates, or steam-pipes could be laid in the circular trough orbottom M. It will be seen, too, that, as represented, the rotation ofthe pan causes the rollers to revolve.

If desirable, independent driving apparatus could be applied to therollers, so as` to cause them to rotate at a different surface-speed toto that of the pan.

Having now described my invention, and

the best mode known to me of carryin git into 8o effect, what I claimis 1. The within-described process for producing ground or powderedcaustic alkali, consisting in grinding the alkali while hot or in atemperature sufficiently high to prevent deliquescence.

2. The wlthin-descrlbed process for produc- -ing ground or powderedcaustic alkali, con- 'sistin g in griudin g the alkali While hot, or ina temperature sufficiently high to prevent deli- 9o

